Properties and regulation of the beta-D-galactosidase in Shigella dysenteriae and in Escherichia coli-Shigella dysenteriae hybrids.
Sarkar, S. (Massachusetts Institute of Technology, Cambridge). Properties and regulation of the beta-d-galactosidase in Shigella dysenteriae and in Escherichia coli-Shigella dysenteriae hybrids. J. Bacteriol. 91:1477-1488. 1966.-Shigella dysenteriae strain 60 has a beta-d-galactosidase related to that of Escherichia coli but more heat-sensitive and with a turnover number about 10 times lower. Hybridization by transduction produces strains with enzymes of intermediate properties by recombination within the z gene. Both E. coli and S. dysenteriae have a regulatory i(+) gene. Recombination between i(-) mutants of the two organisms leads to restoration of the i(+) genotype. In S. dysenteriae 60, most of the i(-) mutants are subject to genetic suppression by suppressor mutations at unlinked loci. The effect of these suppressors on the products of the suppressed i(-) genes is discussed.
D002498:Centrifugation; D002874:Chromosome Mapping; D003090:Coliphages; D004794:Enzyme Repression; D004926:Escherichia coli / Q000201:enzymology*; D005696:Galactosidases / Q000378:metabolism*; D005796:Genes; D006358:Hot Temperature; D006824:Hybridization, Genetic; D007106:Immune Sera; D066298:In Vitro Techniques; D007700:Kinetics; D009154:Mutation; D012762:Shigella dysenteriae / Q000201:enzymology*
D007106:Immune Sera; D005696:Galactosidases